The present invention relates to plastic secure packages and more particularly to such packages for having and conveying valuable documents and items and that have tamper evident closures. As used herein, package, envelope, bag and container shall mean equivalent structures.
There are many types of plastic security envelopes with tamper evident features. One common type is shown in FIG. 6 and includes a plastic envelope having a rear panel 100 a front panel 102. These panels could be joined at the bottom by heat seals or adhesives or formed from a single sheet folded back on itself at the bottom 101 as shown in FIG. 6. Side seals, not shown, are formed along both side-edge regions by applying adhesives or hot sealing the internal panel edges together. The upper ends of panels 100 and 102 are joined at 104 by a heat seal extending the width of the bag or by suitable hot melt adhesive as desired. An optional tear off receipt 106, suitably numbered, can be attached to one of the panels via weakened perforations 105.
A generally horizontal slit 108 is formed in front panel 102 to enable the user to introduce documents or items into the chamber of the envelope. A tamper evident sealing member 110 is provided to close and seal slit 108 and provide evidence of any tampering such as using cold dry ice or freon gas or hair dryer heat or clear adhesive tape reinforcement to remove a portion of member 110 to gain access to the housed documents or to give tamper evidency if stress forces are applied to member 110. Common and commercially available member 110 includes a tamper evident tape 116 with hot melt adhesive layer 114 one portion of which is secured to the front panel outer surface contiguous to slit 108. Conventionally, layer 114 can include imbedded graphics such as the word "void" that would appear in response to various stresses or temperatures used for tampering. The remainder of layer 114 is initially protected by a removable paper or plastic liner 112 that prevents premature or unwanted adhesive contact with the panel or any other thing. After the documents and/or items are inserted into the envelope, liner 112 is removed and member tamper evident tape 116 pressed to close and seal across slit 108. Tape 116 functions to give a special visual indication, such as multiple appearances of the word "VOID" or other graphics, if the tape had been subjected to one of several types of tampering or, alternatively, tape 116 may be designed to tear or flake or crack or shrivel to give a visual tamper indication. Various materials are commonly known to provide the above functions.
Although this type of envelope performs with some degree of reliability a technical problem exists because of a common human error in usage. Users of this type of secure package tend to be less than careful in assuring that slit 108 is substantially closed when pressing layer 116 to its closed and sealed position. Sometimes the thickness of the stack of documents or the thickness of items within the envelope cause lips 109, 111 defining slit 108 to separate. Sometimes the user pulls panel portion 109 outward when removing liner 112, then quickly applies layer 114 to the portion 111 of panel 102. On occasion, the user pulls up on the top of the bag with one hand, while releasing the liner and pressing 116 with the other hand. In any case, when improperly closed and sealed the central portion of layer 114 is exposed through the widened slot 108 and when pressure is subsequently applied to tamper tape layer 116 a portion of the inner surface of panel 100 adheres to layer 114, generally as shown in FIG. 7. Thereafter, transport or handling of the envelope on occasion causes the housed documents or items to shift in the direction of arrow A which tends to separate panel 100 from layer 114 in the general direction of arrow B, which in turn stresses layer 114 causing the tape to display, erroneously, a tampering attempt indication. This false tampering indication is costly and time consuming for the users and for the customers whose documents or items are being transported because the receiving entity, such as a bank, will not accept the bag showing tamper evidence and will return it to the sender, such as a department store, for re-packaging and shipment.